Control slide valve



Feb. 25, 1969 SQCHUNG 3,429,341

CONTROL SLIDE VA LVE Filed May 5, 1966 nited States Patent O 3,429,341 CONTROL SLIDE VALVE Herbert Sochting, Vienna, Austria, assigner to Hoerbiger Ventilwerke Aktiengesellschaft, Vienna, Austria Filed May 3, 1966, Ser. No. 547,228 Claims priority, application Austria, May 7, 1965,

A 4,173/65 U.S. Cl. IS7-625.68 Int. Cl. F16k 11/07 4 Claims ABSTRACT F THE DISCLOSURE The invention relates to a control slide valve for pneumatic and/ or hydraulic installations with a casing which is provided with port means for the pressure transfer medium, and with a control piston sealed off by packing rings which is slidable in the casing between two end positions, which control piston, in its two end positions brings one used port each into communication with the supply port and in its middle position between the two end positions, in which middle position it is preferably lockable, shuts oit both ports against the supply port and exhausts them.

Control slide valves of this type, so called four-way slide valves, are already known which are employed for a wide range of control purposes, for example, for the alternate actuation of two working cylinders or of double action working cylinders. The known embodiments are provided with a supply port connected with a source of a pressure transfer medium, two ports leading to the working cylinders and exhaust ports co-related with these, which either lead into the atmosphere or into a collecting container for the pressure transfer medium having a low pressure level. In each end position of the control piston, one of the two working cylinders is charged with the pressure transfer medium and the other working cylinder is exhausted or releived of pressure, whereas in the middle position of the control piston, the supply port is closed and both working cylinders remain in their position of rest.

The object of the invention is to improve the known control slide Valves of this type in such a manner that, when their control piston is in the middle position and when their ports are exhausted, an additional control function can be carried out. For example, this problem is presented in the case of the control of locomotives, cranes and the like when, with the control of the driving operation, a braking device is to be actuated simultaneously.

In accordance with the invention, this problem is solved by the provision of an additional control port which, when the control piston is in its middle position is in communication with the supply port via a passage located in the control piston but when the control piston is in either of its two end positions, is connected to exhaust.

By this simple measure, the tield of application of the four-Way slide valves hitherto known is broadened considerably, since with practically the same means an additional control function can Ibe exercised. For example,

3,429,341 Patented Feb. 25, 1969 in the case of a locomotive which is being reversed by the action of the control slide valve from Iforward travel to rearward travel, by means of the additional control port, the brake can be actuated in such a manner that, when the locomotive has come to a standstill, when the control piston is in its middle position, the brake is automatically applied whereas, on actuation of the control slide valve, the brake is released simultaneously with the pressure impulses for the reversal of the direction of travel of the locomotive. Thus a separate control device for the actuation of the brake can fall away.

The same advantages are obtained in the control of cranes, in the control of working cylinders with one or more positions of rest in their stroke range, and in the case of similar pneumatic or hydraulic installations.

The additional control port may be arranged in the casing of the control slide valve in a like manner as the other ports, in which case communication between the supply port and the additional control port is eliected through a passage provided in the control piston. In order to avoid a consequential increase in the length of construction, both of the casing as also of the control piston of the slide valve, and the provision of a separate packing for the additional control port, in accordance with a preferred embodiment of the invention, the additional control port is provided at one end of the control piston and in it, the co-related passages in the control piston consisting of an axial passage and several radial passages leading outwards from the former. When the control piston is in its middle position, the radial passages are located in the plane of the supply port communicating with the source of pressure transfer agent, and thus, in each end position of the control piston, they enter into communication with the exhaust port. The design of the control slide valve in accordance with the invention is considerably simplified in this embodiment as compared with control slide valves hitherto known.

In accordance with a further characteristic feature of the invention, the additional control port may be provided in a transition piece, located between the end of the casing and the cover closing it. The advantages thus obtained are that, for the construction of a control slide valve in accordance with the invention, the casing of a conventional four-way slide valve may be used, and the control slide valve can, as desired or required, be employed with or .without an additional control port.

In order that the proper functioning of the control slide valve may be ensured, the distances between the various connections in the casing, and the dimensioning of the sub-division of the various spaces separated by packing rings and being in communication with the ports, must be appropriately selected. With the usual arrangements of the packing rings at equal distances along the axis ot the device, a casing results having ports located at different distances. In order to avoid this, in a further embodiment of the invention, when the ports in the casing are located equi-distant from one another in axial direction, the distance in axial direction between the two packing rings sealing off the supply port may be smaller than the distance in axial direction between the other packing rings. The casing used with the conventional four-way slide valves with equi-distantly arranged ports may thus be retained unchanged, and besides this, an increase in the length of construction of the valve as well as of the stroke of the control piston is avoided.

` The invention will be explained in greater detail with reference to two embodiments furnished by way of example and illustrated in the accompanying drawing in which FIGS. 1 and 2 each illustrate one control valve in accordance with the invention in a longitudinal vertical section taken on the axis.

In both embodiments, the control slide valve consists of a casing 1 with a control piston 2 displaceable in axial direction in a cylindrical passage of the casing which piston is sealed against the casing by means of packing rings 3 which are maintained at proper distances from each other by means of distance pieces 4 arranged between them. l'he cylindrical passage t'hrough casing 1 is closed at both ends by means of covers 5 and 6 in which the control piston 2 is guided by suitable bearing surfaces. An actuating lever handle 7 is pivotally attached to one end of the control piston 2 and into the other end a head 8 is screwed, which is provided with recesses or a peripheral groove 9 which are adapted to receive the locking spheres 10'. The spheres 10 are pressed inwards by the helical springs 11 contained in nipples 12 which are screwed into the cover 5.

The casing 1 corresponds in its design to that of a conventional four-way valve slide and is provided with iive ports, namely a supply port 13 through which a pneumatic or hydraulic pressure transfer medium is supplied from the source of pressure transfer medium, two user ports 14 and 15 leading to the users to be controlled, and two exhaust ports 16 and 17 which can discharge into the atmosphere or can lead via conduits connected therewith to a container for a pressure transfer medi-um. Cornmunication between the Various ports is effected by means of the control piston 2 which, to this end, is provided with two constrictions 18 and 19.

In the position of the control piston 2 shown in FIG. l, the supply port 13 is shut off by the control piston 2, and the two ports 14 and 15 are in communication via the corelated constrictions 18 and 19 with their exhaust ports 16 and 17. The ycontrol piston 2 is then in its middle position, in which it is retained by the spheres 10K retained in the peripheral groove 9. On the other hand, in FIG. 2 an end position of the control piston 2 is shown, in which it arrives by moving the actuating lever 7 counter-clockwise, and in which the port 14, is in communication via the constriction 13 with the supply port 13, whilst the supply port is in communication via the constriction 19 with the exhaust port 17. By moving the actuating lever 7 clockwise beyond the middle position into the other end position, the port 15 may be brought into communication with the supply port 13, and the user port 14 with the exhaust connection 16.

In both of these embodiments described by way of example, a control port is provided additional to the ports already mentioned, which in the middle position of the control piston 2 is in communication with the supply port 13 via a passage 201 provided in the control piston 2, whilst in the two end positions of the control piston 2, the additional control port is in communication with one of the two exhaust ports 16 or 17. The passage 20 consists of an axial cylindrical passage provided in the control piston from which radial passages 21 extend outwards, which when the control piston 2 is in its middle position are located in the plane of the supply port 13, and which when moving the control piston 2 into its end positions slide past the packing rings 3 which are located on both sides of the supply port 13, whereby they enter into com munication via corresponding constrictions 18 or 19 with one of the exhausting ports 16 or 17.

In accordance with FIG. l, the additional control port 22 is provided in the head 8 inserted into the end face of the control piston 2 and is in communication via passage 23 in the head 8 with an axial passage 20.

In accordance with the somewhat different embodiment 24 is located in a separate transition piece 25, which is inserted at the end of the casing 1 between it and the cover S. Between the cover 5 and the transition piece 25, a packing ring 26` Iis provided for sealing. Communication between the passage 2()y in the control piston 2 and the control port 24 is in this case eifected via a number of radial passages 27 which are provided in the control piston 2 in the region of the control port 24. T he distance between the packing rings 3l and 26 located on both sides of the control port 24 is designed so long in the axial direction of the control piston 2 that the radial passages 27 remain in port with the control connection 24 over the entire range of the stroke of the control piston 2. In this case, the head 8 is attached to the end of the control piston 2 by means of a screw 28 which, at the same time, closes loff the passage 20 against the outer atmosphere.

The embodiments of the control slide valves illustrated and described are, for example, suitable for the control of the driving operations of locomotives, in which case simultaneously with the setting of a direction of travel the air pressure brake is released. The switching on and off as well las the reversal from forward drive to rearward drive and vice versa are effected via the ports 14 and 15, whereas the air pressure brake to be actuated at the same time is in communication with the additional control ports 22 or 24. In the middle position of the control piston 2 shown in FIG. l, the pressure transfer medium employed for control, for example, compressed air, is supplied by way of the supply port 13 and the radial passages 21, the passage 20 and the passage 23 to the control port 22 from which a conduit which is advantageously exible, leads to the air pressure brake which, in this position of the control piston, is applied.

As soon as the locomotive by an appropriate movement of the actuating lever 7 has been set for forward drive or rearward drive, the brake is automatically released by the control slide valve. This is eiected by moving the control piston 2, for example, into the end position shown in FIG. 2, so that the radial passages 21 slide past the packing ring 3 located on one side of the supply port 13 and come into communication with the exhausting ports 17 by way of the constriction 19, thereby also exhaust the brake conduit which is connected with the additional control port 22 or 24. When moving the actuating lever 7 back into the middle position, the radial passages 21 again come into the eiective range of the supply port 13, so that the brake conduit is supplied with compressed air, and when the actuating lever 7 is moved further into that end position which corresponds to the reverse direction of travel, the radial passages 21 enter into communication with the other exhaust port, whereby also in this control position, the brake conduit is relieved of pressure. The actuation of the brake is thus effected automatically with the changes in the direction of travel of the locomotive by means of the control slide valve employed for effecting the said changes so that a separate device for this and a separate actuating manipulation can be eliminated.

The invention is not limited to the embodiments illustrated by way of example and also not to the uses described of the control slide valve. More particularly, the additional control port may also be provided directly in the casing of the control slide valve in which case, however, for the constriction of the control slide valve a separate casing is essential, and the casing of a conventional four-way control valve cannot be employed.

I claim:

1. A control slide valve for pneumatic and hydraulic installations, comprising a casing which is provided with a supply port, motor ports, and exhaust ports for the pressure transfer medium, and a control piston sealed olf by packing rings which is slidable in the casing between two end positions, which control piston is either of its two end positions connects one motor port each with the supply port and in its middle position, between the two end positions, shuts off both motor ports and exhausts them, a passage being provided in the control piston forming an additional control port which, when the control piston is in its middle position, is in communication with the supply port but in the two end positions of the control piston is, on the other hand, connected to exhaust.

2. A control slide valve as claimed in claim l, wherein the additional control port is provided at and in one end of the control piston, the appropriate passage in the control piston consisting of an axial cylindrical passage and several radial passages leading outwards from the axial 10 passage.

3. A control slide valve as claimed in claim 1, wherein the additional control port is provided in a transition piece inserted at the end of the casing between the latter and the cover which closes the end of the casing.

4. A control slide valve as claimed in claim 1, wherein when the ports in the casing are located equidistant from one another in aXail direction, the distance in axial direction between the two packing rings sealing off the supply port is smaller than the distance in axial direction between the other packing rings.

References Cited UNITED STATES PATENTS 2,547,254 4/1951 Braithwaite 137--62568 XR 2,577,999 12/1951 Christensen 137-625.68 2,645,450 7/1953 Chessman 137-625.68

FOREIGN PATENTS 179,854 5/1922 Great Britain. 495,422 ll/1938 Great Britain.

15 M. CARY NELSON, Primary Examiner.

ROBERT I. MILLER, Assistant Examiner. 

